1. Field of Invention.
This invention is directed, generally, to the field of laser devices and, in particular, to gas flow laser designs.
2. Prior Art.
The vast majority of commercial carbon dioxide (CO.sub.2) lasers sold today are of the tube construction design since this approach is the easiest to build and has proven to be the most reliable. The tube construction design generally follows three basic approaches. The simplest and lowest power approach utilizes an electrical discharge in a water-cooled tube; this approach currently being used in most commercial CO.sub.2 lasers. The power limitation of this approach is approximately 70 watts of output power per meter of discharge length. Another basic approach for constructing high power lasers consists of the so called "convective flow laser", wherein gas is circulated through an electrical discharge region wherein the electrical discharge excites the molecules, heating the gas and producing laser action. The laser gas is then pumped through a cooling section, where the waste heat is removed from the gas, after which the gas is recirculated into the electrical discharge region where the process is repeated. The convective flow lasers do not have a specific limitation as to power output per unit length, since this is dependent on variables such as gas flow speed, gas pressure, etc.
A third basic approach, generally referred to as "gas dynamic lasers", utilizes rocket engine technology. This approach will not be discussed further since it does not have application to the instant invention.
A basic tube type laser design has the advantages that the long, narrow discharge geometry allows good laser beam quality (TEM.sub.00 modes) and the gas can flow through laser discharge at a slow flow rate. However, the major disadvantage of this type laser is the power limitation. Thus, an improvement in the power output of the basic tube type laser would have great commercial value, since it does not involve conversion of the existing designs to convective flow laser designs.